Efficient delivery of therapeutic agents, such as a drug, to a subject in need of therapeutic treatment can be profoundly affected by the characteristics of the delivery vehicle. Aside from activity in vivo, the ideal therapeutic agent can be delivered to a site associated with a disease, condition, disorder, or symptom thereof, where it has a duration of action that preferably is long compared to the duration of the disease, condition, disorder, or symptom. One of the most challenging tasks facing the therapeutic treatment of mucosal gastrointestinal (GI) disorders, and other non-GI diseases, conditions, disorders, or symptoms that can be treated through access to the GI tract, is how to effectively and safely administer therapeutic agents via an oral or rectal route that is relatively non-invasive and acceptable to patients. Morishita and Peppas (2006).
Recent progress in the chemical composition and characteristics of delivery vehicles for oral or rectal administration allows for the sustained release of therapeutic agents from polymer matrices and their controlled delivery to a subject over the course of several days (up to a month). In the current state of the art of oral medications, however, therapeutic agents, such as drugs, are encapsulated in pills or capsules and move along the GI tract in a matter of hours after entering the body. The ideal therapeutic agent would be taken once and would provide adequate local or systemic levels of the active agent for the duration of the disease, condition, disorder, or symptom thereof. One current limitation of such a drug delivery paradigm is the lack of a system that can be anchored to the diseased site for a time sufficient to provide efficacious therapy and to resist expulsion by motility or other physiologic motor activity.